Keyur KhamarCARMEL, IN - SEPTEMBER 08: Jason Day of Australia laughs with his caddie Colin Swatton on the seventh hole before resuming play during the first round of the BMW Championship at Crooked Stick Golf Club on September 8, 2016 in Carmel, Indiana. (Photo by Keyur Khamar/PGA TOUR)

Jason Day has replaced longtime caddie and father figure Colin Swatton ahead of this week's BMW Championship. Day will have friend and former high school roommate Luke Reardon on the bag, a move first reported by Golf Channel's George Savaricas.

Reardon could wind up having a short trial run this season. With Day sitting at No. 28 in the FedEx Cup standings, he needs a solid week at Conway Farms to remain in the top 30 and advance to next week's Tour Championship.

A 12-year-old Day first met Swatton at the Kooralbyn International School in Australia shortly after the death of Day's father. Swatton, the school's golf coach at the time, took Day, now 29, under his wing, and the two have had a successful partnership since, highlighted by Day's win at the 2015 PGA Championship and his ascension to No. 1 in the Official World Golf Ranking.

"I lose my dad at 12 and then meet Colin, and to have him walk the journey with me, have him walk up the 18th hole with me, was just a special, special experience I could never forget," Day said after winning the 2015 PGA at Whistling Straits. "It's just -- an amazing feeling I have."

In June, an even longer player-caddie duo ended when Phil Mickelson and Jim "Bones" Mackay parted ways after 25 years together. Mickelson turned to his brother, Tim, as an interim replacement, while Bones, who will be inducted into the Caddie Hall of Fame this week, took a TV job with NBC/Golf Channel.

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